For example, an information reproduction apparatus (magnetic regeneration circuit), which is applied to a magnetic card reader/writer, etc., that reads F and 2F signals for “0” and “1” signals which have been magnetically recorded by a frequency modulation method, mainly includes the structures as stated below.
In the information reproduction apparatus, a signal (information) recorded on a magnetic card is reproduced by a magnetic head, a peak point is detected by a peak detection circuit after the reproduced signal (an analog waveform) has been amplified by an amplifier circuit, and an output signal is inverted at the peak point so that the signal is shaped to have a waveform of a rectangular wave signal. The rectangular wave signal is a signal subjected to a frequency modulation (F2F modulation), and is demodulated by an F2F demodulating circuit.
However, in peak detection by an analog method, in order to read a card with a large amount of noises and a demagnetized card of low output, a circuit needs to be switched for reading of such cards. Thus, there is a disadvantage that the size of the circuit is increased and the cost is also increased. Also, since the circuit needs to be switched, it is necessary to test a plurality of methods to achieve the reading, and the reading time is increased.
In view of the above, an information reproduction apparatus in which digital peak detection is adopted, and which is adaptable to a recording medium (magnetic card) with varied output without switching a circuit, and is capable of suppressing an increase in the size of the circuit and the cost, and also reducing the reading time has been proposed (for example, refer to Patent Literature 1).